MyDatabase_Dev, is an exact copy of Prod, which I setup a few months back. Now however, I want to update this db with the latest version of prod, but I'm receiving a sql server error.

To update, I'm going to my dev database, clicking "import data", selecting MyDatabase_Prod as the source, checking the box to delete all rows currently in MyDatabase_Dev before updating, and finally, running it. I'm receiving an error though, saying there's an issue with references to foreign keys.

What's the best way to update my dev database, without getting the foreign key errors?

why not backup and restore as a new copy from prod database and drop existing dev? Of course, you've to take care of difference in permissions,principals etc by scripting the existing dev permissions and applying it after the restore